Electronic components such as power diodes, (vertical) power transistors or other components must be mounted on substrates. Because of the high currents through such components, it is important to ensure excellent electric and thermal coupling between the components and the substrate.
It is possible to use sintered connections on silver basis (silver sintering) for the mechanical connection between semiconductors and metallic layers, e.g., copper layers, such as the Low-Temperature Connection Technology of Power Electronics (Fortschritt Reports of the VDI, series 21, No. 365, VDI-Verlag), and related methods. In silver sintering, a paste including micro particles or nano particles is compressed under increased temperature and increased pressure; during this process the individual particles coalesce to form a mechanically stable sinter layer and establish a stable mechanical connection between two components abutting the sinter layer.
Because of the different coefficients of thermal expansion of semiconductors and metallic layers, mechanical warping may occur in the sinter layer, which could have an adverse effect on the stability and reliability of the sinter layer.
The printed publication EP 2 075 835 A2 discusses methods for developing sinter layers between a semiconductor chip and a substrate, which can be used to improve the mechanical stability in that the sinter layer is set apart from the edges of the semiconductor chip and interspaces are developed between individual sinter sections.